1. Field of the Invention
This invention relates generally to a tool for hooking pallets or skids, and more particularly, to a pallet hook for repositioning two-way and four-way stringer pallets.
2. Description of the Art
Goods and materials arrive at, and depart from, almost every type of factory or warehouse by unit loads on material handling devices which are typically pallets. A unit load is a number of items, arranged and restrained as one unit on a support platform, so as to be moved and handled at one time, thereby reducing the number of trips required to load/unload items, and consequently reducing handling costs and product damage. In addition to facilitating the efficient handling of large quantities of materials, pallets also serve as a platform base for stacking individual items.
Conventionally, every pallet contains a top deck and bottom deck of wood slats running parallel to each other. Stringers (or runners), which are solid or notched beams running perpendicular to the slats comprising the decks, separate the two decks. In a typical two-way stringer pallet, there are three stringers. The stringers, identified by location, define two chambers between the outside stringers and the interior, or center stringer. The chambers provide the openings for the fork tines of a lift truck or hand jack. The term xe2x80x9ctwo-wayxe2x80x9d indicates that the fork lift can be inserted from either the front or the back of the pallet. In a four-way pallet, the stringers are notched for entry from all four directions. Skids, of course, are pallets with only an upper, or top, deck.
It is a problem, well-known in the art, that a pallet desired to be moved may be in a location that is unreachable by a fork lift truck, or even a hand jack, because of the lack of a dock or ramp, height or width limitations, or weight restrictions. In this case, it is known to solve the problem with a winch, chain, and pallet pullers. Pallet pullers comprise, in one conventional embodiment, a pair of curved gripping heads on arms connected to each other by a pivot, or in some arrangements, a scissoring arrangement. The ends of the arms, distal to the dripping heads, are connected to each other by a short length chain. A chain attached to the winch of a fork lift is then attached to the connecting chain and the gripping heads are arranged to grasp the stringers of a pallet. As the chain is winched in, the gripping heads bite into the stringers and pull the pallet in the direction that the chain is being pulled. It is a disadvantage with this arrangement that the gripping heads are easily detached during use if the chain is pulled at an angle. Stop-and-go pulling causes disengagement, resulting in loss of time, and consequently, additional expense. This is particularly the case when pulling of pallets is done by a lone operator of a high-low fork lift unit, who must dismount and mount the unit each time disengagement occurs. Moreover, since the jaws bite into the pallet wood to grasp the pallet, these pallet pullers damage the pallet. Thus, there is a need for a pallet puller arrangement that will not significantly damage the pallet during attachment and use. In addition to the foregoing problems, conventional pallet pullers are heavy (up to about 21 lbs., for example) and expensive to purchase. There is, therefore, a need in the art for a pallet puller arrangement that is economical, lightweight and convenient to carry and store.
It is also well known to construct pallet pullers, inexpensively, from a piece of metal bent in an L-shape. Typically, the L-shaped pallet pullers have an elongated arm having a length sufficient to hook around the rear of a lower deck board of the pallet to be moved. These pallet pullers are, of course, bulky and inconvenient to carry and store. Moreover, turning the pallet is not an option. There is, therefore, a need in the art for a pallet puller arrangement that can easily be attached to the pallet. The L-shaped pallet pullers also suffer from the disadvantage that they can easily become detached during use.
It is further a problem with all known pallet pullers that there is a xe2x80x9cslingshot effectxe2x80x9d if they become disengaged, or damage the pallet to the point of breaking the stringer or deck wood, or breaking through a joint therebetween. The term xe2x80x9cslingshot effectxe2x80x9d means that the pallet puller and attached chain whip vigorously in the direction that the chain is being pulled. This can damage the materials on the pallet being moved, or surrounding pallets, as well as cause injury to personnel and property. Thus there is a further need in the art for a pallet puller arrangement that will not easily become dislodged during use.
It is, therefore, an object of this invention to provide a pallet puller arrangement that is economical to manufacture, lightweight, and easy to carry and store.
It is another object of this invention to provide a pallet puller arrangement that is easy to attach to the pallet and is retained in position once attached.
It is also an object of this invention to provide a pallet puller arrangement that does not significantly damage the pallets.
It is additionally an object of this invention to provide a pallet puller arrangement that readily enables a loaded pallet to be rotated so as to be reoriented, and pulled.
It is additionally an object of this invention to provide a pallet puller arrangement that resists bending when a heavily loaded pallet is reoriented or pulled at an angle.
The foregoing and other objects are achieved by this invention which provides a pallet puller arrangement that interlocks around a stringer and the lead deck board of a pallet or skid. The pallet puller arrangement is adapted to be used in conjunction with a chain and winch mechanism in order to move a pallet in a desired direction. In an apparatus embodiment, the pallet puller arrangement comprises a unitary body having an elongated principal body portion with an aperture at one end thereof. The aperture is suitable for engaging with a chain quick link or any other suitable engagement means to link a chain to the pallet puller arrangement. Distal to the apertured end, the pallet puller arrangement has an engagement portion for coupling around a stringer of a pallet so as to abut a lead, load-bearing cross-member, or deck board, of the pallet.
In a highly advantageous embodiment of the invention, the engagement portion comprises a stringer cradling portion that is generally perpendicular to the elongated body portion and which is provided a flange extending upwardly from the stringer cradling portion in a direction substantially parallel to the elongated body portion. The upwardly extending flange has a protuberance extending beyond a front face of the laterally extending support surface of the stringer cradling portion in a direction toward the aperture. The protuberance, which has a flat bottom portion that is coplanar with the upper surface of the laterally extending support surface of the stringer cradling portion, is adapted to overlie an interior surface of a deck board. The laterally extending support surface is adapted to accommodate the width of the stringer board.
In operation, the pallet stringer is cradled on one side by the elongated body portion over edge thereof by the laterally extending support surface of the stringer cradling portion and on the other side by the flange. Simultaneously, the protuberance is urged by the user to overlie an interior surface of a deck board, thereby securely hooking the pallet puller arrangement to the pallet. As a result of the hooking mechanism, the arrangement of the present invention is much less likely to disengage during use than known arrangements. Moreover, the pallet puller arrangement of the present invention is much less likely to cause damage to a pallet during use.
The pallet puller arrangement should be constructed of strong, yet somewhat pliable or flexible metal. Tempered steel, for example, is too brittle and could break during use resulting in a slingshot effect. In a preferred embodiment, the pallet puller arrangement is constructed of cold rolled steel.
The metal pallet puller arrangement preferably has a protective coating to prevent rust or other degradation. In a preferred embodiment, the pallet puller arrangement is zinc coated. Illustratively, zinc is plated on the metal (e.g., GM spec 4342-M Code 20U32 zinc plate).
In a specific illustrative embodiment, the unitary body of the pallet puller arrangement of the present invention comprises cold rolled steel, illustratively, 1010-1008 C.R.S. that is 0.230 inches thick. In one embodiment, the pallet puller arrangement is 2xe2x80x3 wide by 2.125xe2x80x3 high by 8.5xe2x80x3 length and has a weight of approximately 20 ounces. Thus, the pallet puller arrangement is small enough to be transported in a user""s pocket. In this embodiment, the stringer cradling portion is adapted to accommodate the width of typical stringer boards and has a length of 2.25 inches. The protuberance extends 0.50 inches beyond the front face of the cradling portion. It is, of course, to be understood that the dimensions and materials are merely illustrative.
In a further advantageous embodiment of the invention, the engagement portion is formed of a stringer cradling portion that is generally perpendicular to an elongated body portion that is reinforced with a bend, whereby the ability to withstand lateral loading without bending is significantly increased. This embodiment of the invention is particularly suited for rotating heavily loaded pallets, particularly 4-way type stringer pallets. As described hereinabove, this embodiment of the invention is adapted to be used in conjunction with a chain and winch mechanism in order to move a pallet in a desired direction. A unitary body has an elongated principal body portion with an aperture at one end thereof. The aperture is suitable for engaging with a chain quick link connector or any other engagement means suitable to link a chain to this further embodiment of the pallet puller arrangement. In one embodiment, the aperture is disposed on the bend of the elongated body portion. Distal to the apertured end, the pallet puller arrangement has an engagement portion for coupling around a stringer of a pallet so as to abut a lead, load-bearing cross-member, or deck board, of the pallet.
This further embodiment of the invention is provided with a flange extending upwardly from the stringer cradling portion in a direction substantially parallel to the elongated body portion. The upwardly extending flange has a protuberance extending beyond a front face of the laterally extending support surface of the stringer cradling portion in a direction toward the aperture on the end of the elongated principal body portion. The protuberance, which has a flat bottom portion that is substantially coplanar with the upper surface of the laterally extending support surface of the stringer cradling portion is adapted to overlie an interior surface of a deck board. The laterally extending support surface is adapted to accommodate the width of the stringer board.
In view of the increased loading to which this further embodiment of the invention might be subjected during usage, there is a possibility that the stringer cradling portion might wedge between the stringer and the deck board, ultimately being pulled out from therebetween. This disadvantageous operating characteristic is resolved by increasing the effective thickness of the stringer cradling portion. Any of several suitable techniques can be employed to produce such effective an increase in the thickness of the stringer cradling portion, including attachment of an additional layer of metal, or the stamping into the metal of a corrugation or dimple, whereby it is ensured that the pulling forces are delivered to the deck board, and not the juncture of the stringer board and the deck board, illustratively the lower deck board.
In operation, the pallet stringer is cradled on one side by the elongated body portion over edge of the pallet stringer by the laterally extending support surface of the stringer cradling portion and on the other side by the flange. Simultaneously, the protuberance is urged by the user to overlie an interior surface of a deck board, thereby securely hooking the pallet puller arrangement to the pallet. As a result of the hooking mechanism, the arrangement of the present invention is much less likely to disengage during use than known arrangements, and permits the application of a lateral force that facilitates rotational reorientation of the pallet. The pallet puller arrangement of the present invention is much less likely to cause damage to a pallet during use.
As previously noted, the pallet puller arrangement preferably is constructed of cold rolled steel. The bend of the elongated body portion affords sufficient structural rigidity to prevent bending of the elongated body portion during application of lateral forces sufficient to rotate most pallet loads. Of course, the required lateral force will vary from application to application depending upon the loading of the pallet and the characteristics of the friction between the pallet and the surface upon which it is disposed.
In accordance with an apparatus aspect of the invention, a puller device is provided for engaging with a pallet of the type having at least a bottom deck formed of a plurality of substantially parallel spaced-apart slats, each slat being fixed to the slat-coupling side of a stringer that extends substantially orthogonal to the parallel slats. The puller device is provided with a puller portion that has an elongated configuration along an axial direction thereof, with first and second ends distal from one another. An engagement portion is fixed to the first end of the puller portion, the engagement portion having a stringer cradling portion fixed to the first end of the puller portion and extending transverse to the axial direction for communicating with the slat-coupling side of the stringer in the region between the spaced-apart slats, and a coupling protuberance fixed to the stringer cradling portion in a region distal from the puller portion for communicating with a surface of a slat directed toward the slat-coupling side of the stringer. Additionally, there is provided a coupler arrangement disposed on the second end of the puller portion.
In one embodiment of the invention, the puller portion is formed of a channel having an L-shaped cross-sectional configuration. The coupler arrangement is an aperture disposed through the bend of the channel having an L-shaped cross-sectional configuration of the puller portion, in the vicinity of the second end thereof. In another embodiment, the coupler arrangement is formed as an aperture that is disposed through the puller portion in the vicinity of the second end thereof.
In a further embodiment, there is provided a flange that extends from the stringer cradling portion, and which is arranged intermediate of the stringer cradling portion and the coupling protuberance. The puller portion has an elongated flat surface substantially orthogonal to the stringer cradling portion, the flange extending from the stringer cradling portion at a portion thereof distal from, and substantially parallel to, the puller portion. Preferably, the puller portion, the stringer cradling portion, the flange, and the coupling protuberance are integrally formed, illustratively of bent metal.
The coupling protuberance is fixed to the flange in the form of an axial protuberance that extends substantially parallel to the puller portion in the direction of the second end of the puller portion. It is important that the stringer cradling portion have a thickness that precludes the stringer cradling portion from being urged between the stringer and the slat during pulling. This is achieved, in certain embodiments, by providing the stringer cradling portion with a bend in the surface thereof to produce a net thickness that is determined to preclude the stringer cradling portion from being urged between the stringer and the slat during pulling.
In accordance with a further apparatus aspect of the invention, there is provided a puller device for engaging with a pallet of the type having at least a bottom deck formed of a plurality of substantially parallel spaced-apart slats, each slat being fixed to the slat-coupling side of a stringer that extends substantially orthogonal to the parallel slats. A puller portion is provided having an elongated configuration along an axial direction thereof, the puller portion having first and second ends distal from one another. Additionally, an engagement portion is fixed to the first end of the puller portion. The engagement portion has a stringer cradling portion fixed to the first end of the puller portion and extending transverse to the axial direction for communicating with the slat-coupling side of the stringer in the region between the spaced-apart slats; a flange extending from the stringer cradling portion; and a coupling protuberance fixed to the flange and extending substantially toward the second end of the puller portion for communicating with a surface of a slat directed toward the slat-coupling side of the stringer. A coupler arrangement is disposed on the second end of the puller portion.
In accordance with a method aspect of the invention, there is provided a method of repositioning a pallet of the type having at least a bottom deck formed of a plurality of substantially parallel spaced-apart slats, each slat being fixed to the slat-coupling side of a stringer that extends substantially orthogonal to the parallel slats. The method includes the steps of:
inserting an engagement device over the bottom deck of the pallet along a first side of the stringer,
cradling the slat-coupling side of the stringer in the region between respective spaced-apart slats;
engaging with the engagement device a stringer-facing surface of a slat; and
applying a repositioning force to the engagement device.
In on embodiment of this method aspect of the invention, the step of engaging includes the further step of drawing a coupling protuberance of the engagement device over the stringer-facing surface of a proximal slat on a second side of the stringer.